Generally, the human skull can be thought of as a fixed volume container. As such, any increase in the volume of the contents of the skull necessarily results in an increase in intracranial pressure (ICP). While there is some normal variation in ICP on a daily basis, elevated ICP beyond the normal range can have substantial adverse effects on the health of an individual. These adverse affects can include loss of consciousness, paralysis, coma, difficulty breathing, and death.
There are many causes of elevated ICP, but the focus of the present application is on intracranial hematomas, which can occur when a vessel in the brain is torn and bleeds. This can occur, for example, as a result of causes as varied as a blow to the head or weakened arterial walls due to an extensive period of hypertension. As used herein, hematomas are defined as abnormal localized collections of blood where the blood is usually at least partially clotted and located inside a bodily organ. Thus, when the brain bleeds, the blood forms clots and is referred to as an intracranial hematoma. Notably, these types of hematomas are dangerous not only because they cause an increase in ICP, but also because they have the capability of shifting the location of other parts of the brain, which can have additional adverse effects on the brain stem.
There are three main kinds of intracranial hematomas: epidural, subdural and intracerebral. While all three types can be deadly if untreated, both epidural and subdural hematomas, also called extra-axial hematomas, occur near the outer part of the brain, close to the skull, and can be treated by creating a burr hole or removing a portion of the skull to relieve the pressure and deal with the hematoma directly. Intracerebral hematomas (ICH), however, occur within the brain tissue itself and are much more difficult to treat with surgical intervention because they are hard to access without causing additional damage to surrounding brain tissue. Improving patient outcomes is an urgent concern. Approximately twenty thousand Americans die each year due to ICH-related problems and this number is expected to double in the next fifty years.
There are two main treatments: medication and surgery. Medical management usually involves controlling blood pressure and reversing the effects of any anti-coagulants in the patient's system in the hopes that the situation can be resolved in a conservative way. Sometimes, however, whether due to the location, cause, volume of the bleed, or development of edema around the blood clot, surgical intervention is recommended.
Presently used surgical techniques include craniotomy, stereotactic-guided evacuation, endoscopic evacuation, and catheter evacuation, but each has their problems. The craniotomy procedure involves removing a portion of the skull so that pressure is relieved and the hematoma can be removed, but it must be performed in a sterile operating room and is likely to induce further trauma to the brain. Stereotactic-guided evacuation is less invasive than a craniotomy, but requires an enormous amount of equipment, time and cost for a procedure that is ultimately less effective than a craniotomy at reducing the size of the hematoma. Endoscopic evacuation is not well-known to neurosurgeons, is not well-suited to emergency situations and still requires the use of an operating room and general anesthesia. Finally, current catheter-based approaches can be performed in the ICU instead of the OR, but necessitate the use of blood thinners and result in slower than desired drainage of the hematoma. Additionally, repeated catheter placements can cause additional damage to other parts of the brain. None of these existing surgical techniques is particularly well-suited to the treatment and remediation of an ICH.
In view of the foregoing, a need has been recognized in connection with improving upon existing tools and techniques for minimally invasive ICH evaluation and evacuation in a less disruptive and quicker way that does not involve general anesthesia or the use of an operating room.
A need has also been identified for new surgical tools and techniques that maximize the amount of hematoma that is removed while minimizing the damage to surrounding tissue. Additionally, it would be preferable for health care providers to use these new surgical tools and techniques in the ICU instead of the OR due to the approximately three additional hours a typical patient would be required to wait prior to intervention in an operating room setting. With elevated ICP, time is the enemy. Quicker intervention will lead to better patient outcomes.
For a better understanding of the present invention, together with other and further features and advantages thereof, reference is made to the following description, taken in conjunction with the accompanying drawings, and the scope of the invention that will be pointed out in the appended claims.